One of the major products of the tomato processing industry is tomato concentrate. Tomato concentrate has a Standard of Identity. The two outstanding properties of tomato concentrate which are monitored and controlled are: a) the Brix of the concentrate, wherein the Brix is a measure of concentration. The concentration expressed as “total soluble-solids” or in units of Brix that represents the percentage of soluble solids in the liquid phase, or more accurately defined as the measure of the total soluble solids, expressed as if they were sucrose, measured by means of a refractometer. b) Viscosity. The viscosity can be measured by a Bostwick consistometer. Tanglertpaihul and Rao (Journal of Food Science (1987) Vol. 52, No. 2) teach of the influence of pulp content on the flow properties and viscosity of concentrates. The viscosity of tomato juice and tomato concentrate which is obtained thereof is also dependent upon whether a “hot break” or “cold break” method is employed in the process of the preparation of tomato juice. In processing the tomatoes, crushing and macerating allows for the pectolitic enzymes in the tomato to be released from the fruit cells and come in contact with the pectin in the tomato and break it down. Since the pectin is responsible for the consistency of the tomato juice, breaking down the pectin, the breakdown of the pectin results in lowering of the viscosity of the resultant tomato juice. In the “hot break” break method, the macerated tomatoes are heated to a temperature which deactivates the pectolitic enzymes, hence preventing the breakdown of pectin. Tomato juice prepared by the “hot break” method exhibits a higher viscosity, and it is generally accepted that said juice and tomato concentrate prepared thereof is of better quality then the same products prepared from the “cold break” method.
The preparation of concentrates is generally conducted by evaporating water from tomato juice. Gould (Tomato Production Processing & Technology, third edition, p. 201-217, CTI Publications Inc.) describes a standard process for preparing tomato juice which includes sorting and trimming fresh tomatoes to remove stems or unripe portions of the tomato, chopping and crushing, heating and extraction. The term extraction as employed by Gould is also known in the industry as “finishing” (see Tanglertpaibul and Rao). Extraction or finishing comprises of passing the crushed tomatoes through a fine screen. The tomato juice thus obtained is then concentrated by evaporating water from the tomato juice until the desired concentration expressed in Brix is reached. The Brix value of concentrate is controlled by the amount of water evaporated. However, according to the prior art methods for preparing tomato concentrate the viscosity of the tomato concentrate is a function of soluble solids concentrate expressed as the Brix value. Hence, controlling the Brix of the concentrate will also influence the viscosity. Tanglertpaibul and Rao teach that the viscosity may be controlled by varying the pulp and serum content in tomato concentrate by adding concentrated serum or pulp to tomato concentrate. However, their method is not practical for conducting on an industrial scale, since it requires a source of pulp and serum, both of which are valuable components of other tomato products which are not readily available, and thus their method would not be financially sound. Furthermore, the mixing of serum or pulp into tomato concentrate on an industrial scale presents technical difficulties due to the viscosity of the concentrate.
Accordingly, there is a long felt need for an industrial scale process for preparing tomato concentrate, wherein the viscosity of the concentrate may be controlled.
It is therefore an objective of the present invention to provide a process for obtaining tomato concentrate wherein the viscosity of the tomato concentrate may be controlled during the process.
It is another objective of the present invention to provide a process for obtaining tomato pulp, a versatile tomato ingredient, wherein said tomato pulp has improved properties. A further objective of the present invention is to provide a method for controlling the viscosity of tomato concentrate and tomato juice.
A further objective of the present invention is to provide a method for preparing tomato concentrate of 30.degree. Brix with more tomato flavor without effecting its viscosity.
It is yet a further objective of the present invention to overcome the shortcoming of the prior art methods.
Other objectives of the invention will become apparent as the description proceeds.